Orthodontic bands have long been used in dentistry to serve as anchoring means for archwires and other dental appliances. The primary purpose of these bands and the appliances they hold is to exert pressure through wires on misplaced or misspaced teeth. It is necessary that the bands fit snugly on the teeth to which they are attached to prevent dislodging under pressure and also to prevent accumulation of food beneath the band and the teeth. Adjustable bands to fit a variety of tooth sizes were first constructed by a French orthodontist in 1841. It was found difficult to obtain conformance to the barrel-shaped contour of many teeth when using these adjustable types; much handwork was necessary to make the band conform and it was also necessary to use large amounts of cement to fill in the areas of non-conformance between the band and the tooth to which it was attached. The adjustable band, for these reasons, gave way to the individually-fitted one. The latter is fashioned by the orthodontist from a ribbon of metal which is formed around the tooth and then welded separately. In a later development preformed bands became available. These could be adapted to individual teeth but the orthodontist needed to stock a large number of bands of differing sizes.
The adjustablility concept was however not forgotten. Boyd et al (U.S. Pat. No. 2,007,517) and Lazarus (U.S. Pat. No. 3,138,872) describe improved adjustable bands but these still require preforming of a metal strip to the approximate shape of the tooth to be banded. Again the orthodontist needs to stock a supply of band sizes and will need to do a considerable amount of fitting for each band.
It is one objective of the present invention to provide an adjustable band which automatically conforms to the shape of the tooth when it is tightened above and below the widest contour.
It is a second objective of the present invention to provide a band having a wide adaptability of differing sizes of teeth so that only two or three sizes need to be stocked. It is a third objective of the present invention to permit continuous adjustment of the band diameter during the course of the treatment to allow changes in applied force or force angle or to compensate for slippage.
These and other objectives of the present invention will be explained in the description with reference to the drawings of which the following is a listing.